Manufacture of crepe yarn



Patented Oct. 29, 1940 UNITED STATES MANUFACTURE OF CREPE YARN Jens Juhl Strube and Au on-the-Main, Germany, a American Rayon Corporation, New

gust Broetz, Erlenbachssignors to North York, N. Y.,

a corporation of Delaware No Drawing.

4 Claims.

The present invention relates to the manufacture of yarn of artificial origin but more particularly refers to the production of threads adapted for use in the manufacture of crepe 5 fabrics.

In th ance with the so-calle the yarn is extruded throu a precipitating medium and then collected on perforated spools. The yarn bodies supported by these spools are then subjected to washing and various other after-treating processes. For the manufacture of crepe yarn it is necessary to size the yarn and to twist it to a much higher degree than usual for ordinary yarn.

In accordance with the process hitherto employed in the manufacture of crepe yarn, the aforementioned after-treated yarn body was first dried on the spool and then wound into skeins whereby a slight twist was imparted to the thread. The artificial silk in skeined form was then subjected to the sizing process which was carried out with solution size as well as with different known watery emulsion sizes. The sized yarn in skeins was then rewound onto spools. In order to provide the filaments with the high degree of twist necessary for yarn used in the manufacture of crepe fabrics, it has hitherto been considered essential to rewind the yarn onto another spool whereby a twist of 2000 turns per meter or more was imparted to the thread. The yarn thus obtained was then in condition for use in the production of crepe fabrics.

In other instances attempts were made to employ a suction or pressure method for the oiling and sizing of the washed yarn packages supported by the perforated spools. In this process the sizing liquid was forced from the outside to the inside of the yarn bodies and through the perforated spinning spools by means of a circulatory pumping system.

It has also been suggested to merely dip the spools supporting the yarn bodies into softening agents and sizing mediums.

In spite of these various suggestions it has so far never been possible to produce satisfactorily sized and finished crepe yarn directly on the spinning spool without rewinding the yarn. The sizing by means of vacuum from the outside to 50 the inside of the yarn body has the disadvantage in that it is difiicult to force the liquids uniformly through the swollen filament bodies. If yarn is used which has been dried on the spools, the uniform distribution of the sizingmedium is 55 rendered even more difiicult. If, however, the

e manufacture of artificial silk in accordd spool spinning process, gh spinnerettes into Application March 4, 14. In Germany March 5, 1

1938, Serial sizing process of the yarn on spools is not carried out absolutely satisfactorily and uniformly, regardless of whether the yarn is carried by the original spinning spool or by a secondary spool, it is not possible to work up the yarn to a first class crepe yarn, without rewinding.

It is therefore one object of the present invention to introduce a process for the manufacture of crepe yarn which shortens the operation and thus offers greater economy.

Another object of the present invention is a method which eliminates the winding of the yarn into skein form prior to the sizing thereof, thus eliminating a step in the usual process.

A further object of the present invention is a method which eliminatesthe rewindingof the yarn for the purpose of imparting a preliminary twist thereto.

Still another object crepe yarn whereby only one employed.

An additional object is a method for the production of crepe yarn which offers a uniform sizing throughout the entire yarn package.

These and other objects will in part become apparent and in part be pointed out from a study of the following specification and appended is a method of producing twisting step is 20 claims.

In accordance with our invention, the yarn extruded through spinnerettes and wound'upon a permeable support, such as for example ordinary perforated spinning spools is washed in accordance with any suitable and known method, for example, in accordance with the suction or pressure washv method and then after-treated, i. e., desulphurized, bleached etc. in order to free the yarn from salts and acids. After the last wet-treating step, however, it is essential that the yarn body not be dried. Immediately after the last wet-treating operation and while the yarn body is still saturated with hot watenthe yarn body wound upon the perforated spinning spool is directly subjected to the sizing process. The latter is carried out in accordance with the pressure sizing method whereby the hot sizing liquid or watery sizing emulsion is forced by means of pressure through the wet yarn body, namely from its inside to its outside. The hot water contained in the washed and after-treated yarn body prior to sizing prevents the cooling of the sizing liquid at the beginning of the sizing operation, thus eliminating irregular precipitations and crustation of the sizing solution in the different thread layers.

Various kinds of sizing s olutions may be used including ordinary sizing emulsion containing fats, oils with or without addition of linseed oil and the like. After the sizing liquid which in most cases has a temperature of from 30 to 40 C. has been forced through the yarn body on the spool for about 3 minutes, the sizing operation is discontinued. It has been found that the sizing of the yarn package from the inside to the outside by means of pressure offers the great advantage that a very uniform distribution of the sizing agent in the yarn body takes place and that no undesirable local coagulations within the yarn body, particularly if emulsion sizes are employed, occur which might cause siltings (sliminess) and agglutinations.

It has further been found, in order to remove any trace of agglutination and irregular distribution of sizing fiuid within the yarn body, that it is essential to follow up the pressure sizing process with a subsequent suction treatment. After completing the sizing process. and after the sizing solution has been allowed to flow off from the sized yarn bodies, a gaseous medium, such as for example, air is sucked through the yarn bodies, namely from the outside of the spool through the yarn body and through the perforated spool into the inside of the spool. This operation removes any excessive accumulations of sizing liquid around and between the thread windings, and thus a perfectly uniform sizing throughout the entire yarn body is obtained. The yarn bodies so treated are then subjected to the usual drying process and subsequently to the twisting operation whereby the desired high twist necessary in the manufacture of crepe fabrics is imparted tothe thread. In many instances it is even possible to eliminate the aforementioned drying step, since the very efiicient suction treatment after sizing makes it possible to twist the yarn without subjecting it to a special drying process. Owing to the uniform sizing and intensive suction after sizing it is thus possible to carry out the crepe twisting operation in only one single step, i. e., the untwisted yarn from the spinning spool is directly twisted into the finished crepe yarn whereby any desired number of to the thread.

Having thus described our invention as required by the patent statutes, what we claim is:

1. In the process of producing crepe yarn,'the steps which comprise collecting artificial silk in a hydrated form on a permeable support to form a wet yarn body thereon, removing impurities from said yarn body by wet treatment, forcing a sizing solution through said yarn body from the inside to the outside thereof, and then removing excess sizing solution from said yarn body by sucking a gaseous medium through said sized yarn body from the outside to the inside thereof.

2. In the process of producing crepe yarn, the steps which comprise collecting artificial silk in a hydrated. form on a permeable support to form a wet yarn body thereon, removing impurities from said yarn body with hot water, forcing a sizing solution through said yarn body from the inside to the outside thereof, and then removing turns may be imparted excess sizing solution from saidyarn body by sucking a gaseous medium through said sized yarn body from the outside to the inside thereof.

3. In the process of producing crepe yarn, the steps which comprise collecting artificial silk in a hydratedform on a permeable support to form a. wet yarn body thereon, removing impurities from said yarn body by Wet treatment, forcing a sizing solution through said yarn body from the inside to the outside thereof, andthen removing excess sizing solution from said yarn body by sucking air through said sized yarn body from the outside to the inside thereof.

4. In the process of producing crepe yarn, the steps which comprise collecting artificial silk in a hydrated form on a permeable support to form a wet yarn body thereon, removing impurities from said yarn body by" wet treatment, forcing a sizing solution having a temperature of about 30 to 40 C. through said yarn body from the inside to the outside thereof, and then removing excess sizing solution from said yarn body by sucking a gaseous medium through said sized yarn body from the outside to the inside thereof.

JENS JUHL STRUBE. AUGUST BROETZ. 

